A man who allegedly masturbated on three women in crowded New York subway trains in 2002 and 2005 has finally been arrested after police identified his semen.

According to DNA Info (via New York Magazine), a man named Darnell Hardware (yes, really) allegedly masturbated against three young woman on separate occasions in packed subway cars until he ejaculated on them. Investigators collected semen from the woman's clothes, but couldn't identify it until last month, when Hardware was convicted of a drug charge. At that time, police took a sample of his DNA and found it matched the subway semen. Hardware's now being held on bail and goes to court September 19.

The case is a victory in the fight against subway perverts. It's also a reminder of the importance of testing for DNA in sexual assault cases. As Neal Baer and Mariska Hargitay pointed out last year, New York has been doing a good job of this, at least when it comes to rape kits — it eliminated its backlog of untested kits in 2003. But other cities have yet to follow suit, and the arrest of Hardware should remind them that DNA can catch a sex offender even long after his crime has been committed — if somebody actually tests it.